CS1 Standard Demo Page

/*
 *A program to perform some basic operations on a list of Strings
 * using java streams.
 */
package arraylistplay;

import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;

public class StreamArrayListProcessing {
    public static void main(String[] args){
        //Point a

        List names = new ArrayList<>();
        names.add("Holiday, Billie");
        names.add("Claudel, Camille");
        names.add("Picasso, Pablo");
        names.add("Gallen-Kallela, Akseli");
        names.add("Zotto, Osvaldo");

        List firstNamesList = names.stream()
                .map(n -> firstName(n))
                .collect(Collectors.toList());

        System.out.print("First names: ");
        for (String firstName : firstNamesList){
            System.out.print(firstName + " ");
        }
        System.out.println();

        //Point c
        String firstNames = names.stream()
                .map(n -> firstName(n))
                .collect(Collectors.joining(", "));

        System.out.println("First names: " + firstNames);

        //POINT D
        List lastNamesList = names.stream()
                .map(n -> lastName(n))
                .collect(Collectors.toList());

        System.out.print("Last names: ");
        for (String lastName : lastNamesList){
            System.out.print(lastName + " ");
        }
        System.out.println();

        //Point c
        String lastNames = names.stream()
                .map(n -> lastName(n))
                .collect(Collectors.joining(", "));

        System.out.println("Last names: " + lastNames);

        //Point e
        String upperCaseFirstNames = names.stream()
                .map(n -> firstName(n))
                .map(n -> n.toUpperCase())
                .collect(Collectors.joining(", "));
        System.out.println("UpperCase first names: " + upperCaseFirstNames);

        //POINT F
        String hyphenatedLastNames = names.stream()
                .map(n -> lastName(n))
                .filter(n -> n.contains("-"))
                .collect(Collectors.joining(", "));
        System.out.println("Hyphenated Last names: " + hyphenatedLastNames);

        //POINT G
        int totalLength = names.stream()
                .map(n -> n.length())
                .reduce(0, (n1, n2) -> n1 + n2);
        System.out.println("Total length: " + totalLength);

        //POINT H
        int totalLengthFirstNames = names.stream()
                .map(n -> firstName(n))
                .map(n -> n.length())
                .reduce(0, (n1, n2) -> n1 + n2);
        System.out.println("First name length: " + totalLengthFirstNames);

        //POINT I
        int totalLengthOfNamesProduct = names.stream()
                .map(n -> n.length())
                .reduce(1, (n1, n2) -> n1 * n2);
        System.out.println("Product of names: " + totalLengthOfNamesProduct);
    }
    private static String firstName(String directoryStyleName) {
        int positionOfComma = directoryStyleName.indexOf(",");
        String firstName = directoryStyleName.substring(positionOfComma + 2);
        return firstName;
    }
    private static String lastName(String directoryStyleName) {
        int positionOfComma = directoryStyleName.indexOf(",");
        String lastName = directoryStyleName.substring(0, positionOfComma);
        return lastName;
    }
}